private MoreObjects.ToStringHelper newHelper() {
    MoreObjects.ToStringHelper helper = MoreObjects.toStringHelper("klass");
    if (omitNulls) {
      helper = helper.omitNullValues();
    }
    return helper;
  }

  @Benchmark
  int toString(int reps) {
    int dummy = 0;
    for (int i = 0; i < reps; i++) {
      MoreObjects.ToStringHelper helper = newHelper();
      for (int j = 0; j < dataSize; ++j) {